OCEANIC MAMMALS 515 



mer. A certain number of adults seem to spend the winter in 

 the Antarctic, but the number declines to a low point in August 

 or September. After the end of December there is a distinct 

 increase, and the whales push farther south. In the North 

 Atlantic a similar movement probably takes place. At least 

 on the New England coasts finbacks are commoner in summer, 

 following the schools of herring into Massachusetts Bay, for 

 example. 



Although the numbers of finback whales is still large, sta- 

 tistics already indicate that local declines occur where intensive 

 hunting is carried on. Overfishing will undoubtedly lead to a 

 repetition of the depletion suffered by other species, if per- 

 sisted in for a long period. It is therefore a first step in cor- 

 rection of this abuse that the recent International Agreement 

 for the Regulation of Whaling forbids the taking or killing of 

 any finback whale less than 55 feet long. Calves, sucklings, 

 or females accompanied by them are likewise protected, and 

 there are restrictions as to the use of whale-catchers and 

 floating factories and designated periods over which whales 

 may be hunted. Thus in the 1937 regulations, any given area 

 of waters may not be fished for more than six months of a 

 year, and this period shall be continuous. No more whales 

 than a given factory is equipped to handle shall be killed at a 

 time, and the carcass must be as fully utilized as possible. 



Apparently the chief use now made of the oil is in the manu- 

 facture of oleomargarine and soap. 



LESSER RORQUAL; SEI WHALE; POLLOCK WHALE 

 BALAENOPTERA BOREALIS Lesson 



Balaenoptera borealis Lesson, Hist. Nat. Gen. et Partic. Mamm. et Oiseaux, Cetaces, p. 



342, 1828 (Gromitz, Lubeck Bay, Schleswig-Holstein). 

 SYNONYM : Balaenoptera laticeps Gray, Zool. Voy. Erebus and Terror, Mamm., p. 20, 



1846 (coast of Schleswig-Holstein). 

 FIGS.: Andrews, R. C., 1916, pis. 29-42, text-figs.; Matthews, 1938b, pis. 18, 19. 



The Sei whale, as it has come to be called by the whalers, is 

 much like a small finback externally, attaining a length of up 

 to 57 feet. The number of throat folds is less than in the 

 finback, 40 to 62, more or less, including the shorter ones, be- 

 tween the pectoral limbs. These folds end evenly on a trans- 

 verse line well anterior to the unbilicus. The general color of 

 the body above varies a good deal but is some shade of gray, 



